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Archive - Feb 24, 2017

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New Tool to Map RNA-DNA Interactions Could Help Researchers Translate Gene Sequences into Functions

Bioengineers at the University of California (UC) San Diego have developed a new tool to identify interactions between RNA and DNA molecules. The tool, called MARGI (Mapping RNA Genome Interactions), is the first technology that is capable of providing a full account of all the RNA molecules that interact with a segment of DNA, as well as the locations of all these interactions -- in just a single experiment. RNA molecules can attach to particular DNA sequences to help control how much protein these particular genes produce within a given time, and within a given cell. And by knowing what genes produce these regulatory RNAs, researchers can start to identify new functions and instructions encoded in the genome. "Most of the human genome sequence is now known, but we still don't know what most of these sequences mean," said Dr. Sheng Zhong, bioengineering professor at the UC San Diego Jacobs School of Engineering and the study's lead author. "To better understand the functions of the genome, it would be useful to have the entire catalog of all the RNA molecules that interact with DNA, and what sequences they interact with. We've developed a tool that can give us that information." Dr. Zhong and his team published their findings in the February 20, 2017 issue of Current Biology. The article is titled “Systematic Mapping of RNA-Chromatin Interactions in Vivo.” Existing methods to study RNA-DNA interactions are only capable of analyzing one RNA molecule at a time, making it impossible to analyze an entire set of RNA-DNA interactions involving hundreds of RNA molecules. "It could take years to analyze all these interactions," said Tri Nguyen, a bioengineering Ph.D. student at UC San Diego and a co-first author of the study.

Diet That Mimics Fasting May Reverse Diabetes--Periodic Cycles of Fasting Reprogram Pancreatic Cells and Restore Insulin Production

A diet designed to imitate the effects of fasting appears to reverse diabetes by reprogramming cells, a new University of Southern California (USC)-led study shows. The fasting-like diet promotes the growth of new insulin-producing pancreatic cells that reduce symptoms of type 1 and type 2 diabetes in mice, according to the study on mice and human cells led by Dr. Valter Longo, Director of the Longevity Institute at the USC Leonard Davis School of Gerontology. "Cycles of a fasting-mimicking diet and a normal diet essentially reprogrammed non-insulin-producing cells into insulin-producing cells," said Dr. Longo, who is also a professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences. "By activating the regeneration of pancreatic cells, we were able to rescue mice from late-stage type 1 and type 2 diabetes. We also reactivated insulin production in human pancreatic cells from type 1 diabetes patients." The reprogrammed adult cells and organs prompted a regeneration in which damaged cells were replaced with new functional ones, he said. The study, published in the February 23, 2017 issue of Cell, is the latest in a series of studies to demonstrate promising health benefits of a brief, periodic diet that mimics the effects of a water-only fast. The Cell article is titled “Fasting-Mimicking Diet Promotes Ngn3-Driven β-Cell Regeneration to Reverse Diabetes.” In type 1 and late-stage type 2 diabetes, the pancreas loses insulin-producing beta cells, increasing instability in blood sugar levels. The study showed a remarkable reversal of diabetes in mice placed on the fasting-mimicking diet for four days each week. They regained healthy insulin production, reduced insulin resistance and demonstrated more stable levels of blood glucose.

Focus on B-Cells Producing Autoantibodies May Point Way to More Successful Treatments for Rheumatoid Arthritis

Current treatments for rheumatoid arthritis relieve the inflammation that leads to joint destruction, but the immunologic defect that triggers the inflammation persists to cause relapses, according to research conducted at the NYU Langone Medical Center and the University of Pittsburgh. Known as autoantibodies and produced by the immune system's B cells, these defective molecules mistakenly attack the body's own proteins in an example of autoimmune disease. Now, the results of a study published online on January 24, 2017 in Arthritis & Rheumatology suggest that clinical trials for new rheumatoid arthritis (RA) drugs should shift from their sole focus on relieving inflammation to eliminating the B cells that produce these antibodies. "We have developed a test for measuring the underlying autoimmunity in rheumatoid arthritis patients that should be used to evaluate new treatment regimens," says senior author Gregg Silverman, M.D., professor in the Departments of Medicine and Pathology at NYU Langone and co-director of its Musculoskeletal Center of Excellence. "We believe this provides a road to a cure for rheumatoid arthritis." The article is titled “Disease Associated Anti-Citrullinated Protein Memory B Cells in Rheumatoid Arthritis Persist in Clinical Remission.” Rheumatoid arthritis is a chronic inflammatory autoimmune disease that affects 1.5 million people in the United States. The current standard of care begins with methotrexate, a drug that reduces inflammation. It is often followed by drugs that block a molecule called tumor necrosis factor (TNF), which promotes inflammation. Both of these classes of drugs can blunt the swelling and inflammation associated with rheumatoid arthritis and at times even allow patients to go into clinical remission that requires continued treatment.